Semiconductor devices are used in a large number of electronic devices, such as computers, cell phones, and others. Semiconductor devices comprise integrated circuits that are formed on semiconductor wafers by depositing many types of thin films of material over the semiconductor wafers, and patterning the thin films of material to form the integrated circuits. Integrated circuits include field-effect transistors (FETs) such as metal oxide semiconductor (MOS) transistors.
One of the goals of the semiconductor industry is to continue shrinking the size and increasing the speed of individual FETs. To achieve these goals, fin FETs (FinFETs) or multiple gate transistors will be used in sub 32 nm transistor nodes. For example, FinFETs not only improve areal density but also improve gate control of the channel.
While conventional FinFET devices may provide a mobility and/or strain channel, the process by which the channel is formed in such FinFET devices may lead to undesirable results. For example, a source/drain selective epitaxial growth process or an activation anneal process may have a detrimental thermal impact on the channel of a FinFET device. Indeed, the material properties of the channel may change and the strain provided by the channel may be decayed or relaxed.
In addition, the mismatch between the material of the channel and surrounding material (e.g., silicon) may lead to the generation of point or plane crystal defects, especially when the materials are subjected to thermal processes.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.